Center speakers should be 3-ways! Many
center speakers are made from the popular 2-way d'Appolito - and
I've made a few myself - but from a center speaker we need a strong
midrange projection and we need an even horizontal dispersion,
something 3-ways are good at. We need everybody in a 4 seat sofa to
get the same experience. The strong midrange projection makes
understanding speech and vocals more easy and in this respect these
center speakers are no different from the Classic 3-ways (SEAS and
ScanSpeak) recently introduced. The same goes for Ekta, Ekta Grande,
SP44, SP38, all featuring 2-4 inch midrange drivers.

Given the size*, this is a speaker that might
please a lot of people and annoy a few - if any! Smooth is what is - and
efficient too. With a healthy 90-91 dB sensitivity it's 1-1½ dB more
sensitive compared to the mkI - and an easy load for even fairly low
wattage tube amps. I recommend minimum 15-20 watts to get some of the
dynamics. More power always means better grip on cones and better
low-end punch. My 50 wpc GlowMaster KT88 loves it. If you never play
very loud, 5-10 watts will obviously do too - in particular PP designs
having better bass grip.

The Jenzen NEXTcomes at roughly twice the price of the
Jenzen
SEAS ER kit, so what do we get for the money besides gorgeous
looks of nextel coated drivers and silver phase plugs?To my ears we get an overall more refined sound with reduced
colouration and subjectively reduced distortion as these excel drivers
can handle a bit more power before detail smearing becomes apparent. I was anxious to hear if NEXT would prove a significant step up
compared to SEAS ER, and it did. It's smoother, it's more transparent,
it's easier to listen to. The Superior Z caps do their thing for the
midrange and the tweeter's Silver-Z cap is the icing on the cake. The
cherry on the icing is the Crescendo tweeter and I'm almost sorry to
say it does a bit better than the T25.

The Jenzen series of
speakers are meant to offer high-end sound for low-end price, even for
the constructions to come with expensive drivers. As discussed in
Speakers' Corner; what we diy people can do at modest price the speaker
manufacturers cannot, is this: Spoil our drivers with the best of
cabinetry. MDF is cheap and it's no problem making 30-50 mm panels, adding solid
bracing to produce low-resonance enclosure that is often a significant
part of high-priced speakers. I recall Eggleston speakers and the
knuckle tap test suggests a solid log of wood. No problem. Laminate 2 x
22 MDF; add bracing and we have the same thing. And it pays off. Cabinet
resonances add more to the sound than we may think.

The first speaker in the
Jenzen series comes with modest priced drivers, yet delivers a
significant soundstage. Size matters and using drivers with a decent
membrane area means they don't have to move much. In particular for the
midrange this is important and releasing it of the tedious task of
pumping bass, things start developing. Drivers we may have found
delivering harsh upper mids in the common two-way set-up may all of a
sudden deliver crystal clear sound in all of the midrange.

Setting up the finished CNO-25 revealed
a fully grown-up CNO. Sensitivity is increased by 4-5
decibels and the overall bottom end weight is
significantly enhanced. Comparatively it goes louder with
less distortion due to doubling the amount of bass
drivers. Upper mid and treble is the same as for the CNO
and this was what I wanted: Maintain CNO qualities, but
increase power handling and bottom end capability.

These drivers were not only madeto look good, but also to provide a sound clearly
distinguishable from the average. High-end drivers built
on classic virtues. As always we apply to the law of
diminishing returns when we buy expensive stuff. Small
improvements may cost small fortunes. I think these
nextel units are the best sounding drivers SEAS has ever
built.

What about spoiling semi-priced
midbass drivers with super tweeters, super caps and super
coils? Proper cabinet and damping too, obviously. Could
it be we might reveal qualities from these mid-priced
mid-drivers, we otherwise wouldn't?

I am a little serious about
this construction although I never expect to get any
feedback on the design. I have set it up and used proper
wound and baked copper wire coils, Superior Z-caps and
10W MOX resistors. And does it sound good? You bet it
does. Maybe someone might even pick this one in a
blind-test compared to the CNO-mkII.

Semi-dipole from state of the art driversSEAS
W22NY001 + W18NX001 + T29CF001

My Autumn sale was a
goodbye to my Acapella SEas speakers. Drivers,
crossovers, vents, terminals, damping material, wires,
everything but the cabs. You don't ship these caps to
Portugal unless you make huge crates with loads of
absorbent material. So, the cabs stayed and having the
W18 and T29 drivers the only thing left to do was
ordering the W22 bass units - and see if a fairly high
efficient Acapella could be made. The W22 comes with a
huge 134 mm magnet and promises 90 dB sensitivity. Not
bad at all. Maybe the W18 could even be run without any
attenuation.... So, the Acapella NEXT was born.This is not a cheap speaker, but the quality of the mid
and mid-tweeter integration is something special. Can be
driven from even 20 watts SET.

This project is realised in collaboration with John
Eekels, Holland. John was asking for a substitute for the no longer
available SEAS W11CY001and after some search we decided to give the new SEAS
W12CY003 a try. This driver features a classic paper cone with standard
coating on the rear and Nextel coating on the front, giving it a nice
appearance as can be seen below. I have previously done a two-way from SEAS
CA18RLY+22TAF/G (not published) from which I've had some good times, thus the SEAS 22TAF/G tweeter was the one I
wanted to try out in this construction.

The "Poor Man's Stradivari"
made from SEAS CA22RNX + MCA15RCY + slightly modified
27TFFC have been finished. Various tweeters (Vifa DX25TG
and Scan-Speak D2905/9700) have been tried and the
crossovers have been added to the website.Having made an EXCEL version of this speaker (read below)
I returned to the "paper" drivers and this is
how it's going to be. They may not be as neutral as the
EXCEL drivers but they just have "something".
Sensitivity and transient attack to point out two things.Feeding these speakers from my old Garrard 401/modified
Rega RB300/Dynavector 10x5/Copland CTA 505 power amp
provides lots of good moments and secondhand vinyl is
available in truckloads for nothing these days. Click
heading to go to PMS.I have to say the PMS is a hit in terms of feedback from
builders. A lot of people have had fun making 3D drawings
of the cabs and I have feedback from 20+ people building
the PMS. A few have reported back with pics and comments and I hope to
have some more photos of finished projects this year.

The SEAS CA22 was tried in a classical
3-way and it turned out so well that I have launched the
project. The MCA12 is doing excellent and provides a fine
midrange with a wide dispersion and a speedy presentation
that leaves most 6-7" midbass drivers behind. These
paper-coned drivers take some burn-in before delivering
the goods. The tweeter is the 27TFFC, an fine tweeter at
a modest price. Sensitivity is 90 dB/2.8 volts and it's
an easy load on the amplifier. The crossover is a simple
2nd order topology and the overall cost for drivers and
crossover components is around 535 . I have to
admit I have had very little feedback on this speaker. I
know that MDF cabs have very little appeal* and the
classic cab is out of fashion. Maybe some gorgeous veneer
would make a change. I'd pick this speaker any time over
the 2.5 clone/Amish 45-95 and others.

*When I first launched the TJL in MDF test
cabs there was absolutely no response at all. I then made
a digitally manipulated image of the drivers in a very
nice looking yew veneered cabinet - and then things
started rolling. So, do we choose speakers by ear or eye?

The following project describes a 2-way
floorstander slightly smaller than the 2.5 clone. Overall
dimensions are: 19 x 98 x 26 cm (W x H x D). This project
is targeting a better midrange, better treble, bass
comparable to the 2.5 clone and a more moderate-sized
cabinet. Well, can all these requirements be accomplished
in a smaller-size construction? And from what drivers? From the Point75 and Acapella projects, the use of the
SEAS
W18E-001 drivers seemed an obvious choice for a
2-way floorstander. The Fountek JP3
tweeter was chosen for treble, giving great results in
the Acapella construction. What I also wanted to try in
this construction was the use of a passive radiator, and
SEAS provides suitable PRs for 6" drivers. Next to
the PMS, the TJL2W is probably the most popular
construction from these pages. And I would pick the
TJL-T25 any time over the 2.5 clone. Same sensitivity,
deep bass like the clone from an even smaller cab. The
TJL is 556  and the 2.95 "clone" is 478
 for al drivers at e.g. http://www.remo.nl/

I do think I've been writing quite a lot
about the TJL 3-way. The experiences gained from the Ekta
and Zahra made me even more anxious to get started. If
the latter two constructions hadn't come along, I would
have done the TJL3W a long time ago. But events took
their own course and I have been pleased with the results
of the former constructions and the TJL3W was very much
next. The TJL is my favourite among a number of 2-way
floorstanders and you always ask how to make a good thing
better. The TJL shares the limitations of most other
6" + tweeter two-ways: Lack of dispersion in the
upper midrange/lower treble due to the bass driver having
to handle everything up into the treble area despite the
low point of crossover around 2500 Hz. When a single
driver has to pump the deep bass and at the same time
handle the delicate upper midrange and lower treble there
are limitations to the loudness we can expect from such a
design. Suitable for most, but it can't play excessively
loud. However, the TJL3W wasn't made to play excessively
loud, rather to play low.May 2006: Finally got the front panels finished.
"Finished" may often mean another half year
before the final oil rub. The OWI tweeter was the
original set-up and so it ended. Now the front panels
(solid cherry wood) only need some daylight to darken
like the veneer. If you want deep bass and un-coloured
sound from a modest sized speaker, take a look.I do NOT consider the TJL3W a project for beginners.

Despite having a ScanSpeak bass driver,
this construction is placed in the SEAS section due to
the SEAS W15CY001 middriver and a later upgrade with an
8" SEAS alu driver.The Point75A&B describes a loudspeaker project
utilising the same Scan Speak 18W/8535
bass driver as used in the 2.5 clone project. A SEAS
W15CY-001 magnesium midrange driver and an Expolinear
NDRL81 aluminium ribbon tweeter complete the
driver selection. Points of crossover are 300 and 3000
Hz. Main feature of this construction is the midrange
working in dipole fashion, creating an impressive
soundstage, and the ribbon tweeter with its weightless
presentation of upper registers. The bass driver works in
a 24 litre bass-reflex cabinet with a 28 Hz port tuning
giving a more lean and well controlled bass compared to
the 2.5 clone with its somewhat one-note bass
presentation. Fine-tuning and voicing has
taken considerably longer than expected due to the
midrange working as dipole and the overall sound being a
mix of direct and reflected sound. Furthermore, some easy
tweaking of the ribbon tweeter was necessary to open up
the sound and a minor equalisation to smooth the upper
treble.Download Point75A&B pdf file, 2.2 MB: Point75A&B.pdf

The aim of this project is to use the
experience gained from the Point75 to produce a speaker
with greater power handling and SPL capability. In other
words, it has to be able to play loud - and retain all
the qualities from the Point75. In addition to this, some
more weight/warmth in the lower/middle midrange would be
appreciated. The 8535 bass driver is the limiting factor in the
Point75 design, and in case you know the 2.5 clone you
know how loud this one goes. A lot of drivers have been
tested before settling on a range of drivers that
eventually turned into three speaker constructions:Acapella LT95:
SEAS L22RN4X, SEAS T17RE,
Scan-Speak D2905/9500. Unfortunately the
T17RE is no longer available.Acapella LWJ:SEAS L22RN4X + SEAS W18EX001 + Fountek JP3

This is the speaker that is the steady
back-bone in my hifi set-up. Not a particularly
complicated speaker, a standard 3-way with an 8"
bass driver working up to 350 Hz. A 6" midrange
working from 350 to 2500 Hz and a ribbon tweeter taking
over from here. Recently a SEAS T25 dome tweeter is
taking the place in replacement of the ribbon. Some day
I'll make a four-way of this construction just to hear if
it is possible to fully integrate four drivers. Not an
easy task. The ribbon version is a tolerable set-up where
the T25 version has an extra 1-1½ dB in the 1-3 kHz
region providing a more forward presentation.

The Acapella SE is the result of almost one year's work
on semi-dipoles and a lot of experience is build into
this construction. Going from 120 wpc solid state to 50
wpc valve amplification during this period made an extra
2 dB sensitivity appear on the wish list and numerous
8" and 10" drivers have been through the
simulation programme. There is no way around a larger
cabinet if this wish has to be fulfilled with an
equivalent bass extension. The SEAS W22EX001
with almost half the membrane weight compared to the
L21/L22 and a 42 litre bass cabinet volume comes close to
an extra 2 dB sensitivity and the Copland valve power amp
is pleased I should tell.I also wanted to make the cabinet from only 6 MDF outer
panels, thus an overall increase in height to some 120
cm. The cabs are slim like the Point75 when seen from the
side. All these changes meant a new 3rd order bass LP
crossover section and reduced middriver and tweeter
attenuation.Drivers, drawings, crossover, pictures:Download
all Acapella files, 6 MB pdfDownload
cab drawings here. 121 KB, zip file.

7.5 litre vented construction - a fabulous
mini-monitor. This construction was made before I started
my diy-loudspeaker website, and I never found the time to
write anything about it. The drivers here are among my
favourites and the W15CY001 drivers were acquired for the
Point75 dipole speaker and the HIQUPHON OWI was bought
only because I wanted to own a pair of these - probably -
best ever made 19 mm domes. Some people find the OWI
tweeter hard to find, but it's not. The OWI and other
magnificient tweeters are made by Oskar Wroending here in
Denmark and his website is here. You cab buy all
types directly from Mr. Wroending or find a distributors
list here.

I recently had a pair the Fountek NeoCD3
ribbon tweeters and have compared them to the JP3 true
alu-ribbon tweeters. The new tweeters have a ribbon made
from laminated material and will probably be less fragile
compared to the JP3 pure alu ribbons. The easiest way to
try out the Neos was to set up a small monitor and the
SEAS W15CY001 midbass was an obvious choice. You don't
find a much better upper midrange and from a 7.5 litres
cabinet you get a surprisingly deep bass. I also tried
adding a subwoofer from two push-push Dynaudio 21W54s
with a crossover around 60-70 Hz/12 dB and it worked
fine.

One of my friends needed a mini for his
home studio and I suggested the SEAS T14RCY having the XP
membrane material giving an ear-friendly midrange with
excellent transparency. The ScanSpeak D2010/8513 tweeter
in this company is sweet and gently, nowhere near how it
performed with the 18W/8535 driver in the 2.5 Clone. The
8513 tweeter must never be mated with an even slightly
harsh midrange. An even better tweeter option may be the
HIQUPHON OW1. The T14 is getting hard to find and a
replacement system is planned from SEAS CA15RLY +
22TAF/G. To come 2007.